Java开发常见错误

本Markdown编辑器使用[StackEdit][6]修改而来，用它写博客，将会带来全新的体验哦：

• 1.把commons-logging-1.0.4.jar的包放到Tomcat/lib目录下即可：

Caused by: java.lang.NoClassDefFoundError: Lorg/apache/commons/logging/Log;    at java.lang.Class.getDeclaredFields0(Native Method)    at java.lang.Class.privateGetDeclaredFields(Class.java:2583)    at java.lang.Class.getDeclaredFields(Class.java:1916)    at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)    at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:256)    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:132)    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:65)    at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:336)    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:786)    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:307)    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:95)    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5213)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)    ... 6 moreCaused by: java.lang.ClassNotFoundException: org.apache.commons.logging.Log    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)    ... 20 more

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• 2.jar冲突
  jar冲突，把正确的那个tomcat，拷贝过去，或把tomcat下的lib下的所有jar拷贝到对应位置！如果不是这里的jar冲突，还有可能是 两个机器上classpath下的jar 不一样
。但是可以肯定的是jar版本不一致，你可以把exception stack贴出来，是可以找到相应的class和jar的。

23-Sep-2017 11:44:39.928 WARNING [localhost-startStop-1] org.springframework.context.support.AbstractApplicationContext.refresh Exception encountered during context initialization - cancelling refresh attempt org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.AbstractMethodError    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305)    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301)    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:753)    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:835)    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537)    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:446)    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:328)    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4853)    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5314)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:729)    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:976)    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1853)    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)    at java.util.concurrent.FutureTask.run(FutureTask.java:266)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)    at java.lang.Thread.run(Thread.java:748)Caused by: java.lang.AbstractMethodError    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:278)    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:445)    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:710)    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)    at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:372)    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:454)    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:439)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)    ... 25 more